Equity (Reclassifications out of Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Realized investment gains (losses), net	$ (3,752)	$ (336)	$ (2,085)	$ (1,102)
Other income	1,474	643	(1,117)	1,897
Total foreign currency translation adjustment
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Amounts reclassified from AOCI			5	5
Net Unrealized Investment Gains (Losses)
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Amounts reclassified from AOCI			(702)	(501)
Total amortization of defined benefit pension items
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Amounts reclassified from AOCI			140	120
Accumulated Other Comprehensive Income (Loss)
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Amounts reclassified from AOCI			(557)	(376)
Amounts reclassified from AOCI
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Realized investment gains (losses), net	(2)	0	(5)	(5)
Other income	0	0	0	0
Amortization of defined benefit pension items:
Prior service cost	0	0	(1)	0
Actuarial gain (loss)	(70)	(60)	(139)	(120)
Amounts reclassified from AOCI | Total foreign currency translation adjustment
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Amounts reclassified from AOCI	(2)	0	(5)	(5)
Amounts reclassified from AOCI | Net Unrealized Investment Gains (Losses)
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Amounts reclassified from AOCI	156	226	702	501
Amounts reclassified from AOCI | Total amortization of defined benefit pension items
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Amounts reclassified from AOCI	(70)	(60)	(140)	(120)
Amounts reclassified from AOCI | Accumulated Other Comprehensive Income (Loss)
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Amounts reclassified from AOCI	84	166	557	376
Amounts reclassified from AOCI | Net unrealized investment gains (losses) on available-for-sale securities
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Net unrealized investment gains (losses)	112	69	270	329
Amounts reclassified from AOCI | Interest Rate | Cash flow hedges
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Net unrealized investment gains (losses)	9	0	8	(1)
Amounts reclassified from AOCI | Currency | Cash flow hedges
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Net unrealized investment gains (losses)	3	1	4	2
Amounts reclassified from AOCI | Currency/Interest rate | Cash flow hedges
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Net unrealized investment gains (losses)	$ 32	$ 156	$ 420	$ 171